"Very restrictive" is a relative term, if its enough then its enough and theres no advantage to more...

I had a K&N in my '96 Dakota v8 for years, I played with switching it back and forth with a paper filter, even had a friend randomly switch it so I could measure mileage and "feel" without knowing which filter I had. I never could detect ANY difference either in mileage or how the engine felt. I sold that truck with 222,000 miles because the transmission was going, the engine still ran just fine. I gave up on the K&N at ~150,000 miles because as other posters noted I thought cleaning the filter was more work than it was worth.

So my conclusion is there is no advantage in a K&N filter, nor do I think it will "destroy your engine" in any reasonably short time frame. As others have said the real advantage is to those who make and sell the K&N filters.

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Sadly Benz-less